PHP OOP - Model vol. 7

Rozbudowa naszego modelu pisanego w poprzednich lekcjach – dodanie metod min oraz max, których nazwy same się opisują. Do dzieła.

Na początku korzystając ze zwykłego PDOConnection sprawdźmy, jak wygląda nasze query:

$q = $conn->query('SELECT DISTINCT(age) FROM people ORDER BY age ASC LIMIT 1');

print_r($q->fetch()) . "<br>";

// Array ( [age] => 20 [0] => 20 )

Tak samo możemy dostać maksimum:

$q = $conn->query('SELECT DISTINCT(age) FROM people ORDER BY age DESC LIMIT 1');

print_r($q->fetch()) . "<br>";

// Array ( [age] => 30 [0] => 30 )

Można to jeszcze uprościć:

$q = $conn->query('SELECT MAX(age) FROM people');

print_r($q->fetch()) . "<br>";

// Array ( [MAX(age)] => 30 [0] => 30 )

Piszemy zatem:

abstract class Model {

    protected static $conn;
    const OPERATORS = ['=', '>=', '>', '<=', '<', '<>'];

    //(...)

    public static function min($col){
        $table = static::$tablename;
        if(in_array($col, static::$keys)){
            $query = "SELECT MIN({$col}) FROM {$table}";
            $q = static::$conn->query($query);
            return $q->fetch()[0]; 
        }
    }

    public static function max($col){
        $table = static::$tablename;
        if(in_array($col, static::$keys)){
            $query = "SELECT MAX({$col}) FROM {$table}";
            $q = static::$conn->query($query);
            return $q->fetch()[0]; 
        }
    }

}

Ustawiamy PersonModel:

$conn = new PDOConnection();
$conn->connect();
$conn = $conn->getConnection();


class PersonModel extends Model {

    protected static $tablename = 'people';
    protected static $keys = ['name', 'age'];
  
}

$person = new PersonModel();
$person->setConn($conn);

I sprawdzamy:

echo PersonModel::min('age');
//20
echo PersonModel::max('age');
//30

PHP OOP – Model vol. 7